Glioblastoma Multiforme is the most common malignant tumor of the central nervous system. It is resistant to current methods of treatment and is associated with a poor prognosis. The elucidation of novel strategies to kill glial tumor cells is thus an urgent need. The epidermal growth factor receptor (EGFR) gene is amplified and over- expressed in about half of these tumors. Epidermal growth factor acts as a mitogen and over-expression of its receptor may contribute to the excessive proliferation seen in cancer. However, ligand stimulation of cells over-expressing the EGFR also has been shown to induce apoptosis. Thus a key answered question in tumor biology is: what are the factors which determine whether excessive activation of growth factor receptors leads to mitogenesis versus apoptosis? An improved understanding of mechanisms involved in the preferential activation of apoptosis may lead to more effective treatment. Our first approach will e to use inducible transfection systems to determine the threshold of receptor expression in glioma cells whereby a mitogenic signal changes to a death signal. Our preliminary data suggests that over-expression of the EGFR results in the aberrant activation of cell death pathways and leads to the recruitment of key proteins involved in apoptosis such as RIP and Caspase-8 to the EGFR mediated apoptosis in glioma cells in vitro as well as in animal models of glial tumors. The applicant is a board-certified neurologist who has taken care of patients with nervous system tumors and is committed to a career in academic neuro-oncology. The program outlined in this application provides a rigorous and intensive didactic and research experience, which will enable the applicant to pursue a career as an independent researcher. The mentor is the Director of Cancer Biology at Beth Israel Deaconess Medical Center (BIDMC), and has extensive experience in signal transduction mediated by receptor tyrosine kinases. The clinical mentor is a neuro-oncologist who is the Co-Director of the Brain Tumor Center at BIDMC. The academic environment at Harvard Medical School at BIDMC is well suited to pursue the goals outlined in this application.